Detectives swooped in on more than 130 alleged purveyors and possessors of pedophilic images, making arrests and seizing a mound of pictures showing youngsters engaging in sexual scenarios.

“I have seen horrific images ranging from baby boys where their nappies [diapers] have been removed and they have been sexually assaulted by a male, to pictures of naked adolescent children in poses,” said Inspector Peter West of Britain’s National Criminal Squad.

“Also very, very worrying, we have found images of very young children fully clothed that have been identified by pedophiles and who are asking other pedophiles for advice on how to groom them for future abuse.”

As part of the probe, the investigators monitored Internet news groups frequented by pedophiles.

More than 10,000 people visited the sites, but the number of suspects was cut to 440 people who used the sites more than 10 times.

The other nations involved in the probe were Australia, Belgium, Canada, France, Germany, Israel, Italy, Japan, North Korea, South Korea, the Netherlands, New Zealand, Portugal, Russia, Spain, Sweden, Taiwan, Turkey – and the United States.